1. Field of the Invention
The present invention relates to a signal conditioner. Specifically, the invention relates to a signal conditioner that converts electrical control signals in a burner control system.
2. Description of the Related Art
Automatic controllers, such as microprocessor-based devices, are commonly used to control mechanical devices. Such is the case in modern Heating, Ventilation, and Air Conditioning (HVAC) systems, where a controller is often utilized to control heating devices (e.g., burners), airflow fans, heat exchangers, louvers, and the like. The control of these devices is typically based on a plurality of inputs, such as desired temperature setpoints, temperature sensors, time clocks, and fault monitoring. The controller then typically produces one or more output signals that are used to control the mechanical devices of the HVAC system.
Often, the signal or signals produced by the controller are not compatible with the mechanical device to which they are intended control. For example, the controller may produce a variable 4-20 mA signal while a valve requires a variable 0-10 V signal. In such cases a signal conditioner, also known as a signal converter, may be used to condition, i.e., convert, the signal produced by the controller to one that may be utilized by the mechanical device.
The automatic controllers of HVAC systems have other drawbacks as well. For instance, during start-up and/or power restoration to an HVAC system, the output signals provided by the controller could damage the mechanical device and/or result in inefficient operation. Furthermore, failure in a temperature sensor or a program fault may result in the over heating or under heating of a burner and the entire HVAC system.
The present invention is aimed at solving one or more of these deficiencies or other deficiencies in the prior art.